The present invention relates to a display comprising a plurality of light-emitting or light-detecting semiconductor components in an essentially monocrystalline substrate transmissive to generated light. A front side of the substrate is provided as a light exit surface on which at a spacing from one another respective electric contact electrodes for the individual semiconductor components are provided. On a rear side of the substrate corresponding individual respective counter electrodes are provided in correspondence with the front side electrodes.
In German patent application No. P 33 10 362.3 of Mar. 22, 1983, incorporated herein by reference, a method for the manufacture of a display comprising a number of luminescent diodes or photo-receiving diodes is described which are preferably arranged in an array. In such an array, it is important that individual luminescent diodes and/or photo-diodes do not mutually influence one another in an undesired fashion, i.e. that optical cross-talk is reduced to at least a permissible minimum extent.
The luminescent diodes and/or photo-diodes in such an array, are arranged on or in a substrate member comprised of semiconductor material and at intervals from one another. Upon activation of a specific luminescent diode (in contrast with non-activated adjacent luminescent diodes) only this one activated luminescent diode is to be perceived as light-emitting. The corresponding applies to photo-diodes in which only the one specific diode, for example, is to emit a detector signal. This optical selectivity stands in contrast to the effect that, in the case of substrates which are greatly transparent for the radiation to be emitted, or for the radiation to be received, a more or less great reflectivity occurs on the interior surface of its rear side. The respective front side of the substrate is that particular side through which the light, in accordance with specifications, is to be emitted or received.
A specific reflection on the rear side of the substrate is thoroughly desirable per se insofar as it extends in areal fashion to the region of the respective diode and does not effect any radiation overshooting, or any such receiving sensitivity which renders the diode more or less distinguishable in relation to adjacent diodes. Such a desired reflection can be provided as a consequence of the presence of the respective counter-electrode applied on the rear side of the respective diode.
In order to avoid the above-described undesired optical cross-talk, in the above referred to German application, the elimination of an entire-surface metal layer initially present from the manufacture, except for the counterelectrodes, is provided for in the surface areas of the rear side of the substrate. In this German patent application, for this purpose it is proposed to conduct a light radiation through the substrate with a wave length for which the substrate is transparent, which is operated in a pulse-wise fashion, and which is so intensity-strong that the respective area fractions of the rear-side metal layer are at least initially melted, but preferably entirely eliminated. The electrodes on the front side of the substrate thus act in a self-adjusting fashion as masks, so that the counter electrode portions of the original metal layer of the rear side remain within the shadow effect projection of the contacts of the front side.
The result of the manufacturing method of the above cited German application is a substrate which has on the front side and the rear side oppositely disposed electrodes and counter electrodes for the individual light-optical semiconductor components. The interstices of the rear side of the substrate between the counter electrodes are essentially free of a reflecting metal layer. Such an arrangement, although manufactured according to different, but considerably more complicated, methods has even been known per se.